See void bleapputils_delayUs(UINT32 delay) in bleapputils.h, where parameter delay is in microseconds you want to delay. Note that this is a busy wait (spinning in a loop). If the device takes an interrupt while in this loop, then it may run longer than delay microseconds. Make sure that this is not over a few milliseconds (thumb rule is ~10mS; use timers for longer delays). PWM is really the best option.